Starting with version 4.0.0, the Variable element from Template Builder and Maven Add-in is replaced with Global Variables defined in Query Builder. With this change, you only need to create them once and then use them further in the Template Builder and Maven Add-in.
But if you like to have things the old way, there is an option to do so by redefining the useGlobalExpressions attribute in the Settings field.
Here are quick instructions: